Me = confused.

Here's the thread:

https://honda-tech.com/zerothread?id=324343&page=2

Someone please set us straight!

 

http://www.tirerack.com/wheels/tech/offset.htm



[Modified by Geezer, 2:49 PM 3/3/2003]

 

You have it backwards. Lower positive offset moves the mounting surface closer to wheel centerline and moves the wheel towards the outside of the car.

So that an ET45 offset + 10mm spacer = ET35 offset.

 

Ok, i see where your confusion is:



In this picture, lets say the offset is 40mm. If you were to get a huge 40mm spacer, you'd effectively fill the offset gap, hence making the offset 0mm, since the mounting surface would be the same as the centerline.

Now once you get to zero offset, if you add say, another 10mm spacer you would now have negative 10 offset and your logic would now apply. But not before you get into negative offset...

 

Black R is wrong.

Offset is just the distance from the centerline of the wheel to the wheel's mounting surface. A 10mm spacer will reduce a 45mm offset to 35mm offset wheels by decreasing that distance. Make sense?

 

 

i did some calculations to see which offset on a 15x7 put the rubber on the ground in the same proportion as the type R's stock wheel. i'm looking at what percentage of the tire patch is in front/behind of the hub mounting surface plane (extend wheel-to-hub mating surface to ground). my biggest concern with getting 15x7 wheels is putting stress on the hub in a unintended direction (ie not stock!).
1 inch = 25.4mm
oem R 6" wide wheel = 152.4mm
width to centerline = 3" = 76.2mm
if you add 50mm (oem R wheel is 50+ offset) to 76.2mm = 126.2mm = distance from inside rim lip to mounting surface (where hub touches the inside of the wheel). the wheel carries 83% (126.2/152.4) of the car's weight inside the hub's mounting plane and 17% outside of it.
whether on not this makes any sense, it would take a 15x7 wheel with a 58+ offset to put the rubber on the ground in the same proportion as stock.
other 15x7 wheel dimensions of interest:
38+: 71/29
43+: 74/26
45+: 75/25
i think all this jibberish is ultimately useless because many people are running around with different offsets and have no hub damage. i guess you should just buy wheels/tires that will fit in fenderwell with no lca or fender contact.

 

Yes it is, LOL...

 

ha! there are a few important ideas to take from this. it turns out the location of the inside rim lip (38+ 15x7 wheel) is the same distance to the lca as the oem wheel. however, the outside lip is 25mm closer than stock to the fender.
the 45+ 15x7's inside lip is 8mm closer to the lca and 18mm closer to the fender. it also keeps the tire patch location closest to stock of these 3 offsets (most common on aftermarket wheels).
43+ 15x7: inside lip 6mm closer to lca, 20mm closer to fender.
my 205/50 azenis on stock R wheels already rub the frame on the front of the car in full lock. i'm most interested in the 15x7 43+ stern aguzze wheels, but i'm concerned with increased rubbing of the frame. my thinking is since the 205 tire remains the same width and now it won't be pinched on a 15x6 (bulging sidewall), i shouldn't have much trouble with the wheel being 6mm closer to the frame.


[Modified by magic hat #9, 11:21 AM 3/4/2003]

 

Wrong, assuming your calculations are correct, the bulging or not bulging wont affect the rubbing, since the bulging doesn't make the tire wider, but narrower and taller.

If the inside of the new wheel is closer to the LCA it means that it will rub that much sooner....with the same tire on..

Matt

 

Assuming your math is correct, that would make sense since 25mm~1in which is the difference in width vs. stock...

 

[QUOTEmy 205/50 azenis on stock R wheels already rub the frame on the front of the car in full lock. i'm most interested in the 15x7 43+ stern aguzze wheels, but i'm concerned with increased rubbing of the frame.[Modified by magic hat #9, 11:21 AM 3/4/2003][/QUOTE]

What have you done with your suspension that 205/50/15 azenis on stock wheels rub? I got the stern uglies w/ azenis combo, and will install them later this week when the weather is nicer. My car is 3/4" lower than stock. I will post if I have any rubbing issues.

 

Maybe someone can suggest the proper offset for a high HP turbo EG w/ 17 x 8.5"
wheels.
8.5" Half of wheel width = 108mm
Stock 5" half of wheel width = 63.5mm
stock off set = ?
Desired offset = ?

Also, how evil are spacers assuming I have longer wheel studs?

thanks
Ben

 

.....that helped me a LOT. Thanks jsi!